Li Anhua and his wife Shi Huaju met 12 years ago and make their living as street food vendors outside a university in Shanghai. Here, they drove their motorcycle pulling a food cart in a suburban area of Shanghai.

Li Anhua and his wife Shi Huaju met 12 years ago and make their living as street food vendors outside a university in Shanghai. Here, they drove their motorcycle pulling a food cart in a suburban area of Shanghai.

Shanghai is one of China's most expensive cities. The couple's 2000 yuan ($320) monthly income is just enough to support their family and rent a tiny room in their native Sichuan province for their two children, who are taken care of by their grandmother.

Shanghai is one of China's most expensive cities. The couple's 2000 yuan ($320) monthly income is just enough to support their family and rent a tiny room in their native Sichuan province for their two children, who are taken care of by their grandmother.

On Jan. 27, the couple started their long trek home for the Spring Festival, or the Chinese Lunar New Year, traveling for 50 hours by train and bus during peak season to see their children after a long year of separation.

On Jan. 27, the couple started their long trek home for the Spring Festival, or the Chinese Lunar New Year, traveling for 50 hours by train and bus during peak season to see their children after a long year of separation.

Every year, millions of migrant workers travel to their hometowns during the Chinese New Year, a massive movement of people that is considered the biggest migration of people in the world in such a short period. Here, the couple waited in line at a train station in Shanghai on Jan. 28.

Every year, millions of migrant workers travel to their hometowns during the Chinese New Year, a massive movement of people that is considered the biggest migration of people in the world in such a short period. Here, the couple waited in line at a train station in Shanghai on Jan. 28.

Public transportation authorities expect about 3.41 billion journeys by train, flight and bus to take place nationwide over the weeklong Chinese New Year holiday. Pictured, people rested between train carriages near Yinyu, Jiangxi province.

Public transportation authorities expect about 3.41 billion journeys by train, flight and bus to take place nationwide over the weeklong Chinese New Year holiday. Pictured, people rested between train carriages near Yinyu, Jiangxi province.